function copy_source(pkg_name)
    -- 首先判断是不是要拷贝源码如果有就不需要拷贝
    if os.exists("third_party/"..pkg_name) then
        return
    end

    local outdata, _ = os.iorun("xrepo.bat info "..pkg_name)
    local pkg_path = nil
    for k in string.gmatch(outdata, "([%w%p]+)") do
        if string.find(k, pkg_name) and string.find(k, "cache") then
            pkg_path = k .. "/source/"
            break
        end
    end

    if not os.exists(pkg_path) then
        print("拉取库: "..pkg_name.."失败")
        return
    end
    print("拉取库: "..pkg_name.."中。。。")
    os.cp(pkg_path, "third_party/"..pkg_name)
    print("拉取库: "..pkg_name.."成功!")
end